Flow of water in a sponge is from ostia to canals to ............. to osculum,

Answer

To answer the question regarding the flow of water in a sponge, we will break down the process step by step.

### Step-by-Step Solution:

1. **Understanding the Structure of a Sponge**:
- Sponges belong to the phylum Porifera and are multicellular organisms characterized by their porous bodies.

2. **Identifying the Entry Point**:
- Water enters the sponge through small openings called **ostia**. These are inhalant pores that allow water to flow into the sponge's body.

3. **Water Flow Pathway**:
- After entering through the ostia, the water travels through a system of canals. This is where the sponge's unique canal system comes into play, facilitating the movement of water.

4. **Identifying the Next Structure**:
- The water then moves into a central cavity known as the **spongocoel** (also referred to as the paragastric cavity). This is the large central cavity of the sponge where water collects after passing through the canals.

5. **Exiting the Sponge**:
- Finally, the water exits the sponge through a larger opening called the **osculum**, which is an exhalant pore.

### Complete Flow of Water in a Sponge:
- Ostia → Canals → **Spongocoel** → Osculum

### Final Answer:
The blank in the question should be filled with **spongocoel**.

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